The Performance

There are four basic pillars to SSD performance that I like to look at: random read, random write, sequential read and sequential write speed. A good SSD must be strong in all four categories, but some are more noticeable than others. Random read and write speed, particularly of small files (e.g. 4KB) are normally what make our desktop hard drives feel so slow. These random operations are everything from file and table updates to search queries and loading applications; they aren't random over the entire space of the disk but they are random enough to bring conventional hard drives to their knees.

Sequential read/write speed is what you encounter when copying large files. How quickly you can move a Blu-ray image around is determined by these values. I've run all four tests on these drives using IOMeter. I also test all SSDs in a completely used scenario where each LBA/page has been touched, at some point, with valid data. Brand new, out of the box, performance will be greater but not over the life of the drive. If you want to know more about why this is and how I test, I suggest consulting The SSD Anthology.

Sequential read performance is basically maxed out for these drives; we're bottlenecked by the SATA bus at this point (300MB/s minus some overhead). We won't see sequential read performance improve until the 6Gbps SATA protocol starts appearing in controllers. The X25-M G2 is basically the same speed as the previous gen here.

Sequential write performance has always been a bottleneck on the Intel drives. There's a small 7% performance improvement from the new drive, but it's still much slower than any other MLC drive in its class. Pushing higher speeds isn't an issue for the controller as the SLC X25-E actually posts our fastest numbers here.

While I don't believe that 70MB/s write speeds are terrible, Intel does need to think about improving performance here because the competition is already far better. The more important values are still random read/write performance, but sequential write speed is an area that Intel continues to lag behind in.

The real strength of the Intel drives is in its random, small file, read/write performance. Here we see a 10% improvement in random read performance over the 1st gen drives, putting the new X25-M ahead of even the X25-E. Now there are obvious lifespan benefits you get from an SLC drive that the G2 can't match, but for a desktop user this thing is even better than the X25-E.

None of the competitors can touch the X25-M here; Intel is 50% faster than the closest MLC contender. It's tough to read but the WD VelociRaptor scores a 0.68MB/s score here.

These are the same results as above but I'm reporting average latency instead of average transfer rate. It gives you a bit of the idea of the scale of performance here. I had to remove the WD VelociRaptor because its read latency threw the chart's scale off, it averaged 17.3 ms here.

And the X25-M G2's true strength: random write performance. Once again, we're faster than the X25-E and nearly 40% faster than the X25-M G1. None of the Indilinx or Samsung drives can touch Intel here.

The Samsung RBB controller does not seem to like worst-case random writes on a well used drive, it's actually slower than the VelociRaptor here. This is what I've seen in my earlier investigations as well. It actually helps explain why the older Samsung based SSDs in Apple notebooks never really felt all that fast.

Final Words...for now

The X25-M G2 appears to be everything Intel said it would be. It's anywhere from 0 - 40% faster than the 1st gen drive in these low level tests. I would expect to see a 0 - 10% improvement in the real world depending on applications, but that's what I'm off to test next.

I know this is a bit pre-emptive, but i really hope that if the introduction of TRIM goes well that we see a double bar graph showing new AND used performance bars for each drive (ie: TRIM on, TRIM off). Once TRIM is implemented it may level the playing field for some drives and that should be easily and fairly shown in the charts. I know you had shown used vs new benchmarks during the anthology but in different charts sometimes on different pages made it tricky to see exactly the difference. Again, if TRIM is all it's touted to be, "new" state may be, the longterm state of an SSD.

Here's hoping Intel get's it act together with those seq writes.

PS, i own an 50nm 80gb intel, i'm semi ticked intel won't release a firware with TRIM in it, at the same time, it still has the second fastest random read and write (second only to it's newer version) and it feels rediculously fast to me launching every application on my computer at once when i start windows, and a sub 20 second boot time in OSX. Reply

I think computer market will slowdown in the next two years. Industry results in July shows profit warnings and losses in many companies. Intel lost 398 US$ mill and AMD 335 US$ mill.

New Google Chrome operating system (which has lesser hardware requirements than Windows), virtualization runing on multicore computers (one computer, many users) and financial crisis can hit very hard the sales for PC market.

Intel with it's high IOPS, and SSD's in general with their non-existent response time seem poised to dominate multi-user, and virtualization setup's. It does seem like hard times ahead, but that's where bang for buck is really going to count and not to many people actually "need" a 2TB drive, where as HD's have been the bottleneck in computer's ever since the GHZ race spread out into the multi-core arena. SSD's seems ready to stand up in a multi user server, or virtualization setup to take it from "hold on a second i'm on a shared server login" to.. "really, this is a shared computer?" Reply

What makes this even harder to understand is that performance on the drive is dynamic - the algorithms gradually accommodate changing workloads under a fragmented condition. This only happens under LOW free space conditions in the used state.

I copied a lot of files sequentially to the SSD these few days. Seq write speeds increased from 30-40MB/s to over 80MB/s these few days, but random writes dropped to 15MB/s. These are Crystaldiskmark benches so I don't trust them much at all, but seq writes definitely became faster (can't feel the effect of slower random writes).

The performance profile of these Intel drives is VERY confusing. TRIM will probably help a lot to make performance less confusing.